The International patent application number PCT/IB/03/01544 filed on the 11th of Apr. 2003 with a priority date on 30, Apr. 2002 by Koninklijke Philips Electronics describes a new transmission system of the type mentioned in the opening paragraph. It enables a receiver of the former system to receive signals transmitted by the new transmission system. A drawback of this system is that the new modulation scheme adds noise to the signals received by the receivers of the former transmission system, which may disturb the receivers.